Reciprocating compressor



Nov. 1, 1938. w, u ss 2,134,782

REG IPROCA'I'ING COMPRESSOR Filed April 16, 1954 3 Sheets-Sheet 2 INVENTOR I VI/ra" F rness BY ATTORNEY NOV. 1, 1938. w FOURNESS 2,134,782

REC I PROCATING COMPRES SOB Filed April 16, 19254 5 Sheets-Sheet 3 I \NVENTOR I V/Yf' Fa r'nass 5% M ATTORN E V Patented Nov. 1, 1938 I Y UNITED STATES PATENT OFFICE RECIPROCATING COMPRESSOR Wilfred Foumess, Oakland, Calif assignor, by mesne assignments, to Fourness Development Corporation, Ltd.

Application April 16, 1934, Serial No. 720,888 11 Claims. (01. 230-192) This invention relates to a compressor mechacontemplates the use of a combination of intake nism, and especially to one to be used in connecmeans. One of these is a suction valve open durtion with refrigerating systems. In systems ing the suction stroke; and the other of these is that character, it is nowcommon to provide a opened only at the end of the suction or intake 5, fluid refrigerant medium, which can be vaporized, stroke, to provide a flash intake, supplementing as in an expansion coil, and then it is passed to a the action of the suction valve. compressor to be compressed; and the compressed It is still another object of the invention to provapor is then condensed into liquid form. Durvide a simple and effective lubricating system and ing vaporization, there is a corresponding absorpoil seal for the cylinder and piston and their assotion of heat. The cycle of evaporation, compreselated reciprocating mechanism. 10 sion, and condensation, is repeated until the tem- This; invention possesses many other advanperature at or near the expansion coil is reduced tages, and has other objects which may be made to a desired value. more easily apparent from a consideration of one Since the use of mechanical compressors in embodiment of the invention. For this purpose such systems is now well understood, further dethere is shown a form in the drawings accom- 15 scription thereof is unnecessary. panying and forming part of the present speci- It is one of the objects of this invention to imflcatio'n. This form will now be described in deprove in general, reciprocating compressors for tail, illustrating the general principles of the ingaseous or vaporous media. vention; but it is to be understood that this de- In mechanisms of this character, it is importailed description is not to be taken in a limiting 20 tant and advantageous to keep the size and sense, since the scope of the invention is best weight of the compressor to as low a value as posdefined by the appended claims. sible, and yet maintain adequate capacity of the Referring to the draw system. One factor toward accomplishing this Fi 1 8 8 S elevation 01 a p ss e 5 result is that of high speed operation. This'high bodying the invention, the end cover being speed operation however, introduces further removed, and the right hand cylinder as well as a problems in the construction of the compressor. portion of the associated parts being shown in By the aid of this invention, high speed opsection; eration of a reciprocating type of compressor is Fig. 2 is a sectional view of the compressor rendered highly eflicient, and it isaccordingly antaken along plane 22 of Fig. 1; 30 other object of this invention to make it possible Fig. 3 is a detail sectional view, taken along to operate etficiently a reciprocating compressor plane 3-8 of Fig. 1; I at speeds as high as 1800 revolutions per minute. Fig. 4 is a fragmentary side elevation of a yoke Such speeds are especially advantageous, since utilized in connection with the reciprocating 5 electric motors, operating from sixty cycle altermechanism; hating currentmains, are also capable of efli- Fig. 5 is a sectional view, taken along plane 5-5 ci'ent operation at equivalent speeds. The invenoiFig. 2, but with a portion of the oil disc broken tion however is not limited to high speed comaway; pressors, as it may be used quite effectively for Fig. 6 is a detail section of the right hand cylin- 40 lower speeds. der and piston, showing the positions of the valves 40 The compressor can be built with one or more at an intermediate position of the suction or sets of cylinders and pistons. At the high speed intake stroke; of operation specified, it is apparent that the cyl- Fig. 7 is a detail view of the right hand cylinder inder space during the intake phase of the cycle and piston, showing the positions of the valves should be filled with as much of the medium as at the end of the suction or intake stroke; 5 possible; and. it is also highly advantageous to Fig. 81s a detail section of the right hand cylinensure that the discharge port stays open only der and piston, showing the positions of the valves during the actual discharge period, so as to preat an intermediate position of the compression vent any back flow of the compressed medium stroke;

upon beginning of the intake stroke. It is an- Fig. 9 is a view similar to Fig. 8, but showing 50 other object of this invention to provide a valve the positions of the valves at or near the end structure for high speed operation, that makes it of the compression stroke; a possible to attain these results. Fig. 10 is a rear view of the discharge valve In order to facilitate the filling of the cylinder closure; and

chamber during the intake stroke, the invention Fig. 11 is an end view of one of the pistons, the 55 suction valve closure being partly broken away.

In the present instance, a pair of cylinder blocks i and 2 as well as a corresponding pair of pistons 3 and 4 are provided. These pistons and blocks are coaxial, and can be arranged in opposed relation with respect to a supporting intermediate casing 5 (Figs. 1, 2, 5). In order to hold. the blocks I, 2 to the casing 5, each of these blocks can be provided with an intermediate flange 6 or 1 (Figs. 1 and 6), respectively cooperating with bosses 8 and 3 on the sides of the casing 5. The inner ends of each block I, 2 can be accommodated in apertures formed in casing 5, and bolts such as It can be used for tightening flanges 5, 1 against bosses 3, 9 in a fluid tight manner; if necessary, by the aid of gaskets.

Since both of the cylinder blocks i, 2 and pistons 3, l are of substantially identical construction, only cylinder block I and piston 3 will be described in detail. The cylinder block i has external annular cooling fins H (Figs. 1 and 6). The outer end of the cylinder block i is closed by a cylinder head H, the construction of which is shown to best advantage in Fig. 6. This .head telescopes over the beveled end of the block 1, and is attached to the flange l2 as by cap screws IS.

A chamber I3 is formed intermediate the end wall of head H and the corresponding end of the block 1. Into this chamber the compressed refrigerant is permitted to pass during the end portion of the compression stroke. The valve mechanism to accomplish this result will be hereinafter described. It is here sufficient to note that the head II has a tapped hole H into which a pipe elbow l5 can be screwed. A pipe connection It (Fig. 2) extends from elbow [5 into one of the upper corners of the casing 5, thus carrying the compressed medium into the casing. The

interior of casing 5 is thus maintained at discharge pressure. The pipe connection I! (Fig. 1) serves correspondingly to lead the compressed medium from the cylinder block 2 into the easing 5.

The compressed medium in casing 5 is withdrawn therefrom as needed, through an oil and gas separator l8 (Figs. 1 and 2), and through the outlet pipe l9. Separator l8 can be of any convenient fonn, and can be provided, if desired, with appropriate screening and draining elements. It serves to prevent any substantial amount of lubricant from passing out of casing 5, said lubricant forming a pool in the bottom of the casing and serving to lubricate the moving parts in a manner to be hereinafter described.

The intake for the cylinder block I is provided by atapped hole 20 (Figs. 6, 7, 8 and 9) leading to an enlarged portion 2| of the cylinder bore, forming an inlet chamber. An elbow 22 connects to the inlet aperture 20, and a pipe connection 23 connects elbow 22 to the source of the medium to be compressed. A pipe connection 24 serves a similar purpose for block 2. For convenience, both pipes 23 and 24 can lead to opposite arms of a common four-way connector 25 (Fig. 2). One of the remaining arms can connect to a common inlet pipe 26; and the last arm can be plugged by a screw member 21, fastened into a boss 28 on casing 5. Thus member 21 can conveniently serve as a support for the inlet connections.

The construction of the piston member 3 can be best described in connection with Figs. 1 and 6. The piston can conveniently be termed a double trunk piston, the-inner portion 23 serving as a guiding stem in that portion of the cylinder bore which is to the left of the enlargement 2|. This portion 29 is preferably provided with a plurality of annular oil grooves 30 to carry oil into the cylinder bore from the interior of casing 5, whereby the oil serves not only as a lubricant but also as a liquid seal for the cylinder bore.

The piston proper 3 is located at the outer end. and engages that portion of the cylinder bore which is to the right of the enlargement.2 l. Between portions 29 and 3 is a. reduced portion 3E, formed by beveled or conical surfaces 32, 33. In the present instance, the intake valve structure is incorporated with the piston 3. Thus there are a plurality of apertures or passageways 3 having axes parallel to the axis of the piston 3, and having centers falling on a circle having its center on the axis of the piston. These passageways extend entirely through the piston 3, so that gaseous or vapor medium to be compressed can pass through them from the enlarged bore 2E, to the cylinder chamber 35.

A closure 36 in the form of a disc is adapted to close the apertures 34, but moves away to uncover these apertures during the'suction stroke. The direction of the suction stroke is indicated by arrow 3? in Fig. 6. The valve closure 36 is arranged to be accommodated in a shallow recess38 in the end of the piston 3. It is furthermore guided and limited in its axial movement by the aid of a central post 39. This post has a threaded reduced part 40 engaging in a threaded central aperture in piston 3. A set screw M? can be used to lock post 39 in place. The inner end 4| of the unthreaded portion engages snugly against a corresponding shoulder around the threaded central aperture. The post 39 passes through the valve closure 36 and has a head. 42 for limiting the motion of closure 36 from the closed position of Fig. 8.

The distance through which the closure 38 is permitted to move to uncover the ports or passages 33 can be quite short, since even a short movement can provide a rather wide annular passageway around the edge of closure 36 for the intake gases. The passage of the gases during intermediate portions of the intake stroke is indicated by arrows 43 in Fig. 6. The axial separation of closure 36 from the cooperating surface of piston 3 can be in fact as small as three-sixtyfourths of an inch.

Such small valve movements are especially use- -i'ul with high speed reciprocating mechanisms,

since very little time is taken up to produce full opening when the suction stroke begins. Furthermore, the carrying of the suction valve closure 36 on a post 39 supported on the piston also assists in rapid valve opening. Just as soon as piston 3 reverses at the end of its compression stroke (illustrated in Fig. 9), the inertia of closure 36 acts to cause it to move, relative to piston 3, to the open position.

During the entire suction stroke, the apertures 34 are thus uncovered, and the gases or vapors to be compressed can enter into chamber 35. However, since the speed of the compressor is quite high, such gases may comprise less than the weight which the compressor can effectively compress in a cycle. Accordingly, a supplemental intake is provided, which is effective just preceding the end of the suction stroke.

This result is accomplished by placing the chamber 35 in direct communication with the enlarged portion 2| of the bore, by passing piston 3 completely out of the chamber 35. This position is shown in Fig. 7. Here the intake can 76 occur past the edge of piston 3, from portion 3|, directly into chamber 35. There is thus formed a narrow annular passageway between portion I2 and chamber 35; and although it is narrow, yet it extends entirely around the periphery of piston 3. The gases and vapors are thus free to fill the whole chamber 35 just before the compression stroke.

The supplementing of the intake openings 34 in this manner is of considerable importance in increasing th efficiency of the mechanism; and this is especially the case when the speed of the compressor is high.

The inertia of the closure 36 also assists in hastening the closing of the intake passages 34 immediately upon the beginning of the compression stroke. The direction of the compression stroke is indicated by arrow 45 at the lower portion of Fig. 8. Just as the piston 3 reverses its motion and starts to move in the direction of arrow 3, closure 36 is immediately seated. The advancing edge of piston 3 also closes the left hand end of chamber 35, so that the charge of gas and vapor in in this chamber is now subjected to compression.

Upon suflicient movement of piston 3 to the right, the pressure in chamber 35 becomes sufficiently great to open a discharge valve, the structure of which will now be described. The entire right hand end of chamber 35 is arranged to be closed by a disc closure 46 (Figs. 6, '7, 8, 9, and 10) guided in recess I3. This closure is urged toward closing position by the discharge pressure effective on its face, in chamber I3; but this closing action can be supplemented by a compression spring 41. One end of this spring abuts against the end wall 48 of the hollow spring housing 49. Thishousing is formed integral with the cylinder head II. The other end of spring 41 encircles a boss 50 on the closure 46.

Upon suflicient pressure being attained in chamber 35 during the latter part of the compression stroke, the closure 46 is lifted against the action of spring 41 and of the outlet pressure.

The compressed gases then pass through the slots 5| (Fig. 10) in the periphery of closure 46, into chamber I3 and thence outwardly through port I4 and elbow I5. Spring 41 is just strong enough to prevent too wide an opening of closure 46. It is also to be noted that the head 42 of post 33 can enter a corresponding recess in the closure 46 at the end of the compression stroke.

A complete cycle of operations for one cylinder and its piston can now be summarized. At the beginning of the suction stroke, the piston 3 is in the position of Fig. 9, and is moving toward the left. Closure 46 closes the end of cylinder block I. Due to the rapid reversal of the piston travel, closure 36 by inertia, opens very quickly. The valve positions are then as shown in Fig. 6. The medium to be compressed enters chamber 36 throughout substantially the entire suction stroke, via elbow 22, aperture 26, chamber 2I, and apertures 34. At and near the end of the suction stroke, the medium to be compressed can also pass around the peripheral edge of the piston 3 directly from. chamber 2I into chamber 35. This condition is illustrated in Fig. 7 I

Directly upon reversal of movement of piston 3 to begin its compression stroke, the'valve closure 36 is moved by inertia to closing position. It stays closed thereafter until the compression stroke is completed. Upon the arrival of the piston 3 to a position where the gas pressure in chamber 35 can overcome the combined action of spring 41 and of the outlet pressure in chamber I3, valve 46 lifts, and the compressed gases can flow through slots 5| into chamber I3, and out through aperature I4 and elbow I5. This position is shown in Fig. 8.

Should any oil or other foreign matter be trapped in the cylinder space 35, the valve 46 is forced open by it as soon as the space 35 is reduced to that of the body of oil or foreign matter. The valve 46 opens widely and the oil is quickly ejected without any material stresses being created in the mechanism.

This description of the compression operation applies equally well to the operation of the piston structure 4 in the cylinder block 2.

Both of the coaxial piston structures 3, 4, can be reciprocated by a common mechanism. As shown most clearly in Figs. 1 and 2, casing 5 has formed therein, an upper track 52 and a lower track 53. These can be supported as by integral legs 54, and each of them can be provided with a vertical guide surface 55. Guided for movement on the tracks 52, 53, and abutting the guide surfaces 55, is a yoke structure 56. This yoke structure is substantially rectangular in outline, its upper and lower edges cooperating with the guides and tracks. Its side members can be reinforced as by ribs 51 and are respectively detachably keyed to the inner ends of the piston structures. In this way, reciprocation of the yoke 56 causes a corresponding reciprocation of the piston structures.

One way in which the keying between the yoke 56 and the pistons can be accomplished is indicated in Figs. 3 and 4. Each of the inner ends of the piston structures 3, 4 carries a projection 53 that has an enlarged head 59. The yoke structure 56 carries at each side a slotted member 60, the slot 6I thereof being disposed in a horizontal direction and being just wide enough to engage the projection 58 beneath the head 59. In this way, the yoke structure 56 can be slid into place from the right of casing 5 as viewed in Fig. 2, slots 6| being immediately engageable over the projections 58.

In order to reciprocate yoke structure 56 on tracks 52, 53 in a horizontal direction, an eccentric block 62 is provided. This block is arranged to slide vertically inside the yoke 56 and along its sides. As shown most clearly in Figs. 1 and 3, it has extending vertical edges 63 overlying the yoke sides and serving to confine the yoke structure 56 against movement off the guiding tracks. In order to move the block 62, an eccentric 64 is provided, engaging a circular aperture in block 62. The eccentric 64 is rotatable about an axis 65. In fact, eccentric 64 can conveniently be formed integrally with a driving shaft 66.

In order to hold block 62 against relative axial movement, eccentric 64 can have a rear flange 61 engaging the rear edge of block 62; and a disc 68 can be fastened to the front face of the eccentric 62, and overlying the front edge of the block 62.

It is apparent, without further explanation, that rotation of shaft 66 in either direction, will cause block 62 to rise and fall in yoke 56, and at the same time, yoke 56 will be reciprocated by the block 62 in a horizontal direction. For balancing purposes, a counterweight 69 can be used, integral with shaft 66. If desired, however, this counterweight can serve as an additional eccentric to operate an additional pair of pistons; and of course in general, as many eccentrics and yokes can be accommodated in casing 5 as may be required to increase the capacity of the compressor.

In order to maintain casing 5 fluid tight, so that it may maintain the compressed gases passed into it at the discharge pressure, the casing is closed at the front end by a cover 10, and at the back end by a cover ll. These covers are shown as having flanges overlying corresponding flanges on each side of the casing 5. Through the flanges pass a number of fastening screws 12. Furthermore, each cover can be provided with appropriate journals for supporting shaft 86.

Thus cover is shown as having a boss 13 through which shaft 66 extends, for appropriate connection to a source of power. A bearing sleeve 14 is inserted inside of boss 13. Provisions can be made to prevent fluid leaks around the extending portion of shaft 66. For example, a cap 15 (Fig. 2) can be telescoped over the reduced end of boss 18, and can be fastened thereto in a fluid tight manner as by cap screws 16. Shaft 66 passes through cap 15 with a running clearance. However, a number of compressible or yielding washers 11 can encircle the shaft 66 inside of boss II, to form a fluid tight fit with said shaft. These washers can be held in a cup 18 abutting the inner surface of cap 15; and a compression spring 19 disposed over shaft 66 can be used to urge the cup 18 and washers 11 against the cap 15.

If desired, a thrust ball bearing structure 80 can be provided between the cover 10 and the cocentric 64. This structure can serve to hold the yoke 56, block 52 and shaft 56 in definite axial position.

Cover H can in general be designed in a manner similar to cover 10, to permit shaft 66 to pass therethrough so that the compressor may be driven from either end. However, in this instance, cover H is shown as having a bearing sleeve 8! inside of boss 82, which has a separable cover 83.

In order to provide lubrication as well as an oil seal, a body of lubricant 84 is formed in the bottom of casing 5. It can have a level such as indicated at 85, which is about as high as the lower track guide 53. Oil is passed to the shaft bearings and the pistons in a manner now to be described. An oil disc 86 (Figs. 2 and 5), dips into the oil 84 and carries some of it upwardly. A rib 51 is formed on the inner side of cover H, having a. number of downwardly directed passageways 88. These openings are located on each side of the rib 81, and they all lead into a common radial aperture 89. This aperture is connected to passage 90 in boss 82. Oil can pass from this passage through groove 8| in cap 83, into the long axial aperture 92 in shaft 56. From this aperture, centrifugal force throws lubricant through radial oiling apertures, such as 93, for block 62; and 94, for journal H. Oil of course can pass to the rear bearing sleeve 8| via opening 95. To prevent any oil from being trapped in boss 13, a diagonal passage 96 is provided from the front end of the boss, into the casing 5.

The disc 86 also throws oil on the exposed parts of the piston structures, to provide an oil seal as heretofore explained.

I claim:

1. In a compressor mechanism, a casing, a piston and a cylinder structure supported by the casing, means in the casing for causing relative motion between the piston and the cylinder. includinga shaft, said casing having a body of lubricant therein, and means for distributing said lubricant through the shaft to sliding parts of the mechanism, including means independent of the piston and shaft, forming an aperture radial to the shaft axis as well as apertures transverse thereto and communicating therewith, the outer ends of the apertures being open, and means for passing lubricant into said transverse apertures.

2. The combination as set forth in claim 1, in which the transverse apertures slant downwardly, and in which the radial aperture communicates with an axial aperture in the shaft.

3. In a reciprocating gas compressor, means forming a cylinder space and a piston structure operating in said space, said compressor having an inlet valve adapted to open near the beginning of the intake stroke and to close near the beginning of the compression stroke, said piston structure having an annular surface which is spaced from the walls of the cylinder space near the end of the intake stroke to form an annular inlet passageway supplemental to the inlet valve and which closes near the beginning of the compression, stroke, and remains closed for the remainder of the stroke.

4. In a reciprocating gas compressor, means forming a cylinder space and a piston structure operating in said space, there being an enlarged bore at one end of said space forming an intake chamber, said structure having an inlet port, a valve adapted to open said port near the beginning of the intake stroke and to close it near the beginning of the compression stroke, said structure having an annular surface which is spaced from the walls of the cylinder space near the end of the intake stroke to form a supplemental annular inlet passageway which closes near the beginning of the compression stroke, and means whereby said inlet port is maintained con tinuously in communication with said intake chamber.

5. In a reciprocating gas compressor mechanism, a cylinder block having a bore forming a cylinder, as well as an enlarged bore communicating with the cylinder bore, means forming an inlet passageway to the enlarged bore, a piston structure having a part reciprocating in the cylinder bore, as well as a coaxial guiding part, said block forming a guideway for said coaxial part, beyond the enlarged bore, forming a seal for the cylinder, and means for soreciprocating the piston structure that the inner end thereof, at the end of the intake stroke, passes out of the cylinder bore, said piston structure having one or more passageways forming an inlet port in direct communication with the enlarged bore and the interior of the cylinder, and a valve for controlling said passageways.

6. In a reciprocating gas compressor mechanism, a cylinder block having a pair of spaced coaxial cylinder bores, joined by an intermediate enlarged portion forming an inlet chamber, means forming an inlet passageway to said chamber, one of said cylinder bores forming a compression space and the other of said cylinder bores forming a guideway, a piston structure having a. working end reciprocating in the compression space, as well as a coaxial guiding portion reciprocating in the guideway, said guiding portion forming a seal with the guideway for the compression space and the inlet chamber, and means for so reciprocating the piston structure that the working end thereof, at the end of the intake stroke, passes out of the cylinder bore, whereby the inlet chamber and the compression space are placed in communication.

'7. In a reciprocating gas compressor mechanism, a cylinder block having a pair of spaced coaxial cylinder bores, joined by an intermediate enlarged portion forming an inlet chamchamber.

8. In a reciprocating gas compressor mechanism, a cylinder block having a pair of spaced coaxial cylinder bores, joined by an intermediate enlarged portion forming an inlet chamber, means forming an inlet passageway to said chamber, one of said cylinder bores forming a compression space and the other of said cylinder bores i'orming a guideway, and a piston structure hav-'- ing a working end reciprocating in the compres sion space, as well as a coaxial guiding portion reciprocating in the guideway, said guiding portion forming a seal with the guideway for the compression space'and the inlet chamber, the axial length of said working end being less than the axial length of the inlet chamber, and means for so reciprocating the piston structure that the working end thereof, at the end of the intake stroke, passes out of the compression space and into the inlet chamber, so as to be spaced from each end thereof and unsupported by the compression space.

9. In a reciprocating gas compressor mechanism, a cylinder block having a pair of spaced coaxial cylinder bores, joined by an intermediate enlarged portion forming an inlet chamber, means forming an inlet passageway to said chamber, one 01 said cylinder bores forming a compression space and the other of said cylinder bores forming a guideway, a piston structure having a working end reciprocating in the compression space, as well as a coaxial guiding portion reciprocating in the guideway, there being an inlet passage extending through the working end, a valve to control said passage, said-guiding portion forming a seal with the guideway for the compression space and the inlet chamber, the axial length of said working end being less than the axial length of the inlet chamber, and means for so reciprocating the piston structure that the working end thereof at the end of the intake stroke passes out of the compression space and into the inlet chamber so as to be spaced from each end thereof, whereby the inlet chamber is simultaneously in communication with the compression space and said passage.

1Q In a reciprocating gas compressor mechanism, a cylinder block having a cylinder bore with an enlarged intermediate portion, whereby the bore is divided into a compression space and a guideway, a double truck piston reciprocating in said cylinder bore and having a working end cooperating with said compression space, said working end being of less axial length than the enlargedportion of the cylinder bore, and means for so reciprocating the piston that the working end of the piston is entirely within the enlarged portion of the cylinder bore at the end of the stroke.

11. In a reciprocating gas compressor mechanism, a cylinder block having a pair of spaced coaxial bores, joined by an enlarged intermediate chamber, means forming an inlet passage to said chamber, one of said bores forming a compression space and the other of said bores forming a guideway, a piston structure having a working end reciprocating in the compression space, as well as a coaxial guiding portion reciprocating in the guideway, said guiding portion forming a seal with the guideway for the compression space and the inlet chamber, and means for so reciproeating the piston structure that the working end thereof, near the end of the intake stroke, passes out of the compression space, the piston structure being entirely supported by the guideway, the compression space being placed in communication with the inlet chamber.

' WILFRED FOURNESS. 

